This invention relates to dental and orthodontic appliances, and more particularly to a new and improved palatal expander and method of making and using the same.
Palatal sutural expansion is the first treatment objective in an increasing number of orthodontic treatment plans. The need for expansion is clearly apparent in patients with posterior crossbite. Patients being prepared for mandibular advancement and patients with equal maxillary and mandibular transverse deficiency also are candidates for expansion. Such expansion is provided by an orthodontic appliance known as a palatal expander.
A variety of screw-type dental palatal expanders are commonly available and have been for decades. Previous designs include the following. Banded palatal expanders are comprised of an expansion screw which is anchored to 2 or 4 teeth (usually the first maxillary bicuspids and first maxillary molars). The metal expansion screw is soldered to stainless steel bands which have been pre-fitted to selected teeth. These bands are lined with adhesive and the entire appliance is positioned with all bands sliding gingivally along their respective teeth until the teeth are fully covered. Examples of banded palatal expanders are shown in U.S. Pat. Nos. 3,977,082 and 5,133,659, the disclosures of which are hereby incorporated by reference.
Bonded palatal expanders incorporate a frame work of heavy reinforcement metal rod material (0.036 inch to 0.040 inch rod) which is hand shaped to follow the lingual gingival margin and buccal gingival margin of all teeth to be covered. The expansion screw is soldered to this metal framework. Acrylic is applied in a powder and liquid mixture by hand to this framework and expansion screw. This acrylic is cured, trimmed and polished. This appliance is bonded onto the teeth to be covered after etching of the enamel. Common bonding adhesive similar to that used to place braces is used to coat the inside of the acrylic “cap” and placed over the anchor teeth.
Removable palatal expanders have wire clasps shaped to grip anchor teeth with an expansion screw embedded into acrylic which acts as the “body” of the appliance. The clasps are spring-like and grip onto teeth to retain the appliance.